Anti-inflammatory activity of erycristagallin, a pterocarpene from Erythrina mildbraedii

Erycristagallin, a pterocarpene isolated from Erythrina mildbraedii, was tested in vitro for its antioxidant properties on the stable 2,2-diphenyl-1-pycryl-hydrazyl (DPPH) free radical and on the arachidonic acid metabolism. In addition, erycristagallin was tested on different experimental models of inflammation, such as the acute and chronic inflammation induced by the application of 12-O-tetradecanoylphorbol 13-acetate (TPA) on mice and the phospholipase A(2)-induced mouse paw oedema test. In the carrageenan-induced mouse paw oedema test, the ethyl acetate extract obtained from E. mildbraedii showed anti-inflammatory activity, and erycristagallin was isolated as the active principle. In vivo, erycristagallin significantly inhibited the phospholipase A(2)-induced mouse paw oedema as well as the mouse ear oedema induced by TPA (ID(50)<10 microg/ear). Moreover, it significantly reduced the chronic inflammation and leukocyte infiltration induced by repeated application of TPA. In vitro, erycristagallin inhibited the arachidonic acid metabolism via the 5-lipoxygenase pathway in rat polymorphonuclear leukocytes (IC(50)=23.4 microM), but had no effect on cyclooxygenase-1 metabolism in human platelets, while showing antioxidant activity in the DPPH test. As with other phenolics, the anti-inflammatory activity of erycristagallin may be based on its capacity to inhibit the arachidonic acid metabolism via the 5-lipoxygenase pathway.